In the case of the African butterfly Bicyclus anynana, females develop ornate wings and court males if they spend the larval stage in a dry, cool environment. The reverse occurs, according to Kathleen Prudic from Yale University and colleagues, when the butterflies are exposed to wetter, warmer environments. “As expected, female Bicyclus anynana in warmer moister conditions that mimic the wet season in the native African range were...